In various kinds of electronic devices mounted on motor vehicles, various types of connectors are used for connection to a wire harness. Especially, in a multi-polar connector having the large number of poles, an operation for fitting and inserting a connecting terminal into a connector housing thereof (refer it simply to as a housing, hereinafter) is apt to be complicated. In order to improve an efficiency of the fitting and inserting operation, a request is increased for a cylindrical round connecting terminal which is high in its degree of fit and insertion.
As a connector for a usual round connecting terminal of this kind, a connector is known that is disclosed in patent literature 1. The connector 100 for the round connecting terminal includes, as shown in FIG. 18 and FIG. 19, a housing 101 and a female type terminal 102 inserted into the housing 101. The female type terminal 102 inserted into the housing 101. The female type terminal 102 includes a cylindrical terminal connecting part 103 connected to a male type terminal of a mate side which is not shown in the drawing, a cylindrical neck part 104 having a small diameter and an electric wire connecting part 108 including one pair of electric wire caulking parts 106 and 106 which have substantially the same diameter as that of a base part 105 of the terminal connecting part 103. In a stepped part between the base part 105 of the terminal connecting part 103 and the neck part 104, an annular groove part 109 is formed. The housing 101 is provided with terminal accommodating holes 110 and 111 formed in two upper and lower stages for accommodating the female type terminal 102 and inserting and connecting the male type terminal and an engaging lance 112 formed substantially at an intermediate position of the terminal accommodating holes 110 and 111. An end of a head part 113 of an engaging lance 112 is fitted to the annular groove part 109.
According to the above-described structure, when the female type terminal 102 is inserted into the terminal accommodating holes 110 and 111, since the head part 113 of the engaging lance 112 enters the part of the neck part 104, the female type terminal 102 is engaged with the housing 101. Under this state, when the female type terminal 102 is pulled in a direction for drawing out the female type terminal 102 from the housing 101, the end of the head part 113 of the engaging lance 112 is fitted to the annular groove part 109 and an entire part of the engaging lance 112 is displaced in the axial direction of the female type terminal 102. Accordingly, the female type terminal 102 is engaged with the housing 101 without breaking the engaging lance 112, so that the female type terminal can be prevented from slipping out.